The PA-67-Helistate was not a quad copter, it was a BLIMP propelled by four helicopters. Big difference, the lift came from Helium.
The idiots that designed it should have used computer modeling, maybe they would have found the resonant vibration that destroyed it (much like a very infamous bridge).
who let kanye in here?
from the pics, all of the props are going to rotate the same way. the will be inherent stability issues(gyroscopic rotation)
the successful units have two pairs of counter-rotating props to counter this.
Each fan is mounted on a servo controlled trunnion oriented such that there is a few degrees of thrust vectoring available in the tangential axis. This is the mechanism through which the torque of the fans is canceled.
Ideally, it will also assist in translation and rotation. We’ll see.